Electronic control apparatus



Jan. 4, 1949. A. WINTHER ELECTRONIC CONTROL APPARATUS I 2 Sheets-Sheet 1 Original Filed May 4, 1944 Jan. 4, 1949. A. WINTHER ELECTRONIC CONTROL APPARATUS Original Filed May 4, 1944 2 Sheets-Sheet 2 m mg 20m. 8258 Patented Jan. 4, 1949 ELECTRONIC CONTROL APPARATUS Anthony Win"her, Kenosha, Wis., assignor to Martin P. Winther, trustee, Waukegan, Ill.

Original application May 4, 1944, Serial No. 534,111. Divided and this application April 29, 1946, Serial No. 665,884

1 Claim. 1

This invention relates to electronic control apparatus, and with regard to certain more specific features, to electronic rectifier tube control means.

This application is a division of my United States patent application Serial No. 534,111, filed May 4, 1944, for El ctronic control apparatus, and relates particularly to the current rectifier means disclosed in said application.

Among the several objects of the invention may be noted the provision of improved means for firing electronic tubes so as to efiect a great saving in tube life and avoid erratic action thereof; the provision of means or the class described whereby control of the tubes is made much more accurate; and th provision of means of this class which minimizes unbalanced conditions of firing load between several tubes. Other objects will be in part abvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claim.

In the accompanying drawings, in which is illustrated one of various possible embodiments of the invention,

Fig. 1 is a wiring diagram of a control unit embodying the invention;

Fig. 2 is an illustrative diagram but not to scale of the wave actions of certain rectifier tubes; and,

Fig. 3 is a diagram similar to that of Fig. 2 showing the results of certain resistance adustments.

Similar reference characters indicate corresponding parts throughout the several views of the drawings.

In 1 is shown a wiring diagram of the co tents of a circuit used in certain control units used in the parent applicat on. This circuit has seven main divisions as follows:

(1) A pri cipal D. C. rect fier circuit I;

2) A main or basic voltage supply circuit II with the usual filters and regulators for maintaining constant voltage;

(3) A tilting bridge circuit III;

(47 A manually controlled adjustable reference voltage circuit IV;

(5) An auxiliary machineespeed-controlled reference voltage circuit V;

('3) A clutch speed control circuit VI; and

7) at clutch torque control circuit VII.

Circuits IV and V (adjustable D. C. networks) are connected in voltage aiding sequence and so are circuits VI and VII (adjustable D. C. networks), but the voltage sum from IV and V, and voltage sum from VI and VII, are arranged for voltage opposition. Also, circuits V and/or VII may at will be cut out without changing the opposition relation of the residual voltages. How this may be done will appear.

Referring to the principal rectifier circuit I, similar ones have been described in my Reissue Patent 22,432, dated February 1, 1944, and in Patent 2,277,284, dated March 24, 1942. This circuit 1 consists of a transformer T| having a primary winding connected across the lines L-2 and L3 of the A, C. circuit. The secondary S of this transformer Tl is connected at its opposite ends to the anodes of a pair of threeelement, hot cathode, gas-filled, grid-controled rectifier tubes 1 and 2 of the ha1f-wave type. These tubes require proper grid potential to fire. They are characterized by the fact that the grid of each tube can start the anode current, but cannot shut it off. However, when the alternating anode voltage passes through zero, the current dies out automatically. The efiect of the grid action is to start the respective tube firing at one point or another on one swing or firing loop of the A. C. anode voltage wave. Different total average D. C. currents are passed. as determined by the grid actions. A two-anode control or amplifier tube 3 in the tilting bridge circuit III effects alternate firing of tubes 1 and 2, its anodes being respectively connected with the grids of tubes 1 and 2.

A mid-tap l2 of the secondary S is connected to one end of the field coil CL of a slip clutch EC-2. The coil CL is in the slip clutch EC-2 which has been diagrammed at the'lower part of the figure. The electrical network between the anodes and cathodes of tubes I and 2 inc uding the D. C. load. coil CL, may be referred to as an A. C. potential circuit. To avoid diagram complexit es, the coil CL has been shown tw ce. In the upper part of the diagram it is located in the circuit and in the lower part its mechanical location only is indicated with respect to the field member F-Z, without showing it in the circuit.

The other end of the field coil CL is connected to the mid-tap [3 of a transformer T2, the primary or which is connected across lines Ll and L-2. The opposite ends of the secondary of the transformer T-2 are connected in parallel with the cathodes of the respective tubes 1 and 2. Control of the tubes I and 2 is managed by means of grids 6-5 and G-.--, respectively. Resistances I-t-i limit the current flowing through the grids so that they are substantially voltage con trolled from the anodes of tube 3. When the tubes 6 and '2 fire (which occurs alternately, as will appear), the anodes alternately feed D. C. current to opposite ends of the secondary S. Thus direct current flows from the center tap it of the transformer 'I'-l through the coil CL and to the center tap 53 of the transformer T--2.

Alternating current applied to circuit I from the secondary of transformer T-12 proceeds to the cathodes of the tu es and 2 and is rectified to produce said D. C. current. The transformer T-Z is connected 120 out of phase with respect to the transformer T--l, being connected across L-l, L-2. The effect of this in connection with other parts of the circuit will appear.

In view of the above, it will be seen that the secondary S of transformer T-l applies an alternating voltage to the anodes of the tubes l and 2. Whenever the grid Gi and anode of the tube i are positive enough, its cathode passes current toward the anode and through the clutch coil CL. Thus this tube becomes a half-wave rectifier. The action of the tube 2 is similar, but alternating with respect to the action of tube l. The solid arrows in Fig. 1 illustrate an exemplary flow of electrons when they occur through tube i.

As stated, circuit II is a main reference voltage circuit. By its means, reference voltage is established for setting a main level of potential for controlling the grids of the principal rectifier tubes l and 2. This reference voltage circuit II originates in a secondary component of a transformer T--5, the latter being fed'from the lines L-l and L2. Rectified negative current under a given voltage issues from the cathode of tube '5, induced by the action of the transformer T-5. The cathode is heated by connection XX from a secondary component of a cathode supply transformer T--3, the latter being fed from the lines Lr-2 and L--3. Thus voltage is applied from the mid-tap of T- through points 29, 3* and then to point l1. Here the circuit splits, part of the voltage being applied through resistance R5, and part being applied to the cathode of the amplifier tube 3. The heating element of the cathode of tube 3 is connected to a secondary component ZZ of said transformer I -3. Thus voltage is impressed upon the anodes of tube 3 and the circuit is completed to tube 5 via re-- sistances R--2, RF-3, points l5 and 35, resistance R-6 and choke K--I, back to the cathode of tube 5. The circuit is completed, as indicated by the solid arrows in Fig. 1, whenever tube 3 fires an anode.

Condenser C--l, cold cathode tube resistance R-6 and choke K-l are related so as to effect filtering and regulation to maintain constant voltage conditions in circuits II and III. Tube -l acts as a voltage regulating leak. Details of this type of voltage regulation have also been specified in my U. S. patent application Serial No. 519,783, filed January 26, 1944 (issued as Patent 2,411,122).

Resistance R5 is connected with resistance Rr4 at point l4. Resistance R 5- connects with point 35. The mid-tap it of the transformer I is connected with the point i 3 between the resistances R5 and 3- 2. Resistances R-t, R4, the tube 3, and the resistances R-2 and R--3 considered alternatively, constitute a bridge 4 through which voltage on grids G--! and G-2 is applied.

The rectifier tube 3 has grids G-3 and (3-4 controlling flow of negative electrons to its respective anodes and the respective anodes feed the grids G-l and G--2 of the rectifier tubes l and 2 respectively, resistances Rr-i bein used in the circuits of the said grids Gl and G2. Thus when either of the grids (3-3 or G l is relatively negative with respect to the cathode of tube 3, the firing of the latter is suppressed to the respective anode. When either of these grids is relatively positive, the tube fires to the re spective anode. When tube 3 fires, this increases the negative electrons in grid Gl or G2 of tubes l or 2, tending to suppress firing of the relevant one of these tubes. When grid G-l or G2 is starved of negative electrons, that is, when the relative part of tube 3 does not fire, then the respective grid (3-5 or G2 becomes relatively positive and the relevant tube 1 or 2 fires. In short, tubes l and 2 respectively tend to fire when the relevant anodes of tube 3 do not, and vice versa.

The grids G-3 and G- 3 of tube 3 are supplied through resistances R-ll from the secondary of a transformer T-i. The primary of a transformer Tl is energized from the cathode circuit supplied by transformer 'I-2. The circuit from the grids G3 and (1-4 through transformers T& and T2 to lines Ll and L2 may be conveniently termed an A. C. network. The firing voltage for the grids of the principal tubes I and 2 is also amplified through the tube 3 which is of the prop-er type for the purpose.

The transformer T--4 imposes on the grids G-S and Gi of the amplified tube 3 sinusoidal voltages phased 180 apart, which also are respectively out of phase with the respective voltages applied to the anodes of the tubes 8 and 2, because transformer Tl receives its primary supply from the secondar of transformer T--2. It will be noted that transformer 'I'2, which supplies 'I--4, is connected across Wires L-l and L-2 of the A. C. line, and transformer T--i, which affects tubes l and 2, receives its supply from lines Ll and L-3. As will be shown, the sinusoidal voltages on 3 are voltage rider waves on an adjustable D. C. control potential applied from circuits IV, V, VI and VII to point l8 cf T-4. Thus the major portions of the waves applied to grids G! and G2 will be fairly flat, as will appear. Since the anodes and cathodes of tube 3 are connected across the reference volt age of the circuit II, a D. C. current similar in shape to a half-wave rectified current is drawn from the system II, the waves being controlled alternately by the grids G--3 and G-. Since the actions of the grids G3 and G-t alternately make each half of the tube 3 a half-wave rectifier, it will be seen that each anode of the tube passes current alternately in accordance with the A. C. potential developed by the transformer T-4. Hence the form of the D. C. current furnished by the circuit II through each anode of tube 3 is that of a current shaped in accordance with. the wave of transformer 'I' i. Thus a firing action occurs alternately on the anodes of tube 3 and this firing will affect the grids Gl and G 2 alternately and independently. Tube 3 is heated through connection ZZ with T3.

Since the principal tubes 1 and 2 can each be fired only when its appropriate anode voltage is positive, the firing must be and is done during thattime for each tube. Thev anode sine waves IOI, I02. (Fig. 2) applied to tubes I and 2 are shown, the one for tube 1 as a solid line, and the one for tube 2 as a dash. line. The. firing v01tage of tube I is represented by dotted lines I03, and it will be noticed that these dotted lines I03 reappear in succeeding cycles under IOI. Dotted lines I04 represent the corresponding firing voltage line in the succeeding cycles belonging to tube 2. Therefore the dotted linesshow the grid voltages which would be necessary to fire the tubes I 2. Lines I03 and I04. for matched tubes are nearly the same but some variations are tobe expected. The dot-dash line I06 represents the cusped but otherwise fairly flat D. C. voltage wave induced by the combination of the D. C. reference voltage on point l8 of transformer T4, and the A. C. voltage applied to grid G3 of tube 3 by this same transformer T--4. Doubledot-dash line I01 is the corresponding line for grid G-d. The D. C. lines I08 and I01 each come to a peak once under each positive loop of lines I I. and- I02 respectively.

It will also be noticed that waves I06, I01 are inverse to the Waves IOI, I02 applied to tubes I and 2, and represent a series of half-wave type D. C. conditions. These waves I00 and I0! may be shifted up and down by adjusting a resistance R8a (to be described) to effect various firing intersections with lines I03 and I04. This shifts the basic D. C. potential component line L, which represents the D. C, control voltage at I8 of T-4. Fig. 3 illustrates the result of such a shift. Wherever (Fig. 3) the adjustable firing voltage curves I05, I07 intersect the grid-firing voltage curves I03 and I04, the tubes I and 2 will be fired (see the cross-hatched areas), and since the cusps or crests of the curves I08 and I01 are relatively steep and can be made even steeper than illustrated on the drawing, it is possible to sweep these curves through the entire lateral ranges of the firing voltages I03 and I04 much more effec-' tively and with more definite control of the firing point of the tubes. Fig. 3 illustrates the maximum upward adjustment of L and full firing of tubes I and 2. By using the cusps or crests of the waves its, It? to intersect the broad inverted crests of the grid-firing voltage curves I03, I04 and by inverting in respect to the anode voltages. IIiI, I02 applied to tubes I and 2, the action is such as to eliminate any effect of one firing voltage peat: on another.

It is to be understood that the lines I05 and I0! diagrammatically indicate the conditions above mentioned and that there may be minor variations in the particular wave forms which carry out the stated principles. The important principle is. that wherever either curve I06 or I0! intersects grid-firing voltage curve I03 or I04, respectivel to effect firing, the respective curve I06 or I0! is concave upward.

Hence all tendency for so-called Waveoverlap in tubes I and 2 (such as occurred in older systerns) is eliminated. A great saving is effected in tube life and erratic action avoided such as was heretofore caused by different grid-firing voltage curves of different tubes. In other words. the major portions of the curve of the firing voltages I06 and I01 are flat, with the cusps as desired. Thus it is not possible, as heretofore, for the applied A. C. firing voltage substantially to intersect the entire firing voltage at once which with improperly matched tubes would cause one to assume a substantial overload.

Tests made with this equipment indicate that the control of the tubes is much more accurate than by the use of a broad firing control wave with a curving and gentle top, as previously used. This is because the two tubes I and 2 in the single-phase circuit are fired substantially equally due totl'le steepness of the approach between pairs of curves such as I06, I03; I01, I24. Unlike the oldscheme, differences in tube grid-firing voltage curves such as I03 and I00 will result in very little unbalance of firing load carried by tubes I- and 2,

The-mid-tap I8 (Fig. 1) of the secondary of the transformer T0 is connected with circuit VII at I 9 and the mid-tap of transformer T5 is connected with the circuit IV at 28. Circuits IV and V operate in voltage aiding sequence with the voltage from point 29. The circuit IV is a manually adjustable reference voltage circuit and the circuit V is an auxiliary reference voltage circuit.

Circuit IV has a supply transformer T'& which is energized from wires LI and L--2 of the A. C. circuit. Circuit V is energized from a transformer T'|, the primary of which is energized from the A. C. generator GN-I.

In detail, circuit IV consists in a rectifier tube 1, the anodes of which are connected with said transformer TS- energized from line wires L-I and L2. The center tap of this transformer T-6 connects with potentiometers R-8 and R-8a. Potentiometer-R-8 is of the fixed type and points 26 is placed in such a position on RS with respect to point 21 that a desired minimum voltage will be obtained when the circuit V is cut out of action. The resistance R8c includes a manually controlled tap 26a for manually controlling the voltage taken from the circuit IV. A switch SW3 having three components has a normally closed contact at 20 and two normally opened contacts at 29c and 30a. When the two normally opened contacts 29a and 300. are closed and the normally closed contact 28 is opened, resistance R8 is removed and resistance R8o is substituted. On the other hand, when the contacts at 29c, and 30a are opened and the one at 28 is closed, then the resistance R8 is effective and the resistance, R8a is cut out. The circuit IV from points 28 or 29a is completed through the resistance R-I, choke K-Z and through the cathode of the tube 1. A condenser C2 and cold cathode tube 6 serve to maintain constant voltage conditions in this circuit,

In detail, circuit V originates at the anodes of tube 8, being completed through the secondary of'transformer TI, point 23, variable resistance R9, point 24, choke K-4 and the cathode of tube 8. A condenser C-3 serves the usual filtering purposes in association with the choke K4. A switch SW-I has a normally open contact 31 and normally closed contact 32. By closing contact 3I and opening 32, the output lead LD of the circuit IV is connected directly to the terminal 22 of circuit VI. This isolates circuit V. Tube 8 is heated through connection YY with transformer T3.

As stated, the voltages from circuits IV and V and from point 29 oppose the voltage generated by the circuits VI and VII or by one of them. These voltages from IV, V and 29 all are directed to point 22 and pass from that point to the grids G3 and (3-4 of tube 3 via resistance RI0, point 2|, variable resistance RII (or switch element SW2a), mid-point I8 of transformer T4, resistances R-I4 to the grids 6-3 and G-4 of tube 3. In Fig. 1 the voltage eiiects from point 29 to 22 are shown by dashed arrows. Beyond point 22, to the right and to I8, the sum of the voltage effects from IV, V and 29 is indicated by dot-dash arrows.

In detail, circuit VI is constituted by a rectifier tube 9, the anodes of which are connected to the secondary of a transformer T8. The primary of the transformer T8 is supplied by a variable voltage generator GN2 driven from the field'member F-2 of clutch EC2, for example. Voltage from the mid-tap of the secondary of transformer T8 is supplied to point 22 in opposition to the voltage from circuits IV and V. The circuit VI is closed through resistance Rr-IU, point 2| and the cathode of tube 9. The condenser C4 is used for the usual filtering purpose. Local circulation is shown by the wavy arrows. The heater element of the cathode of tube 9 is fed from connection YY of the secondary of the cathode transformer TS. Thus the circuit VI, like the circuit V, does not depend for energization upon the A. C. line, but upon the speed of an independent generator, namely GN-2.

In detail, the circuit VII is constituted by a rectifier tube 10, the anodes of which are connected to the secondary of a transformer T9. The middle tap of a secondary of this transformer T--9 is connected to point 20, the circuit being completed through resistance R,H, point [9, to the cathode of the tube In, the condenser C--5 serving filtering purposes. Local circulation is here also shown by wavy arrows. The voltage of circuit VII is in the same sequence with the voltage from circuit VI, and the sum of these two voltages is in opposition to that from the sum of the sequence voltages from the circuits IV and V and point 29. Point 19 of the circuit VII is connected to the mid-tap 18 of the secondary of transformer T4 through a normally closed element b of a switch SW2. This switch element is by-passed by a normally opened element a of the same switch SW2. Thus circuit VII may be isolated by opening the switch element b and closing the switch element :1. Tube I0 is heated from YY of T3.

The primary of the transformer T9 is energized from the A. C. circuit through means adapted to provide a voltage from circuit VII which is substantially a straight-line function of the torque delivered by the A. C. motor WM. This is accomplished by means of a current transformer 'I--Hl having a primar in the line L--3 and a secondary which feeds the primary of the transformer T-9. Resistance R-IS is connected across the secondary of the transformer T! B. This provides a load.

Voltage transformer TH has its primary connected across the lines Ll and L-2 of the A. C. circuit. Resistance Rl3 is connected across its secondary and has a variable tap 33 connected to the secondary of transformer Tl 0. Point 34 of transformer T-| l is connected to the variable tap 32 of a resistance R-l2. By a suitable adjustment of the resistances R|2 and R-l3, the transformer 'I-! I can be caused to buck down that component of current generated in the transformer TIO as is caused by the magnetizing requirements of the motor WM. The transformer TII is so connected and 32 and 33 are so adjusted that the voltage generated by TIl cancels the voltage generated by the transformer THJ when the motor is idling. Thus the load-ampere curve of the motor is substantially a straight line and the effect is to correct for power factor. The circuit between transformers T9, Tlfl and T|l may be referred to as a transformer circuit component in governing circuit VII for obtaining a straight-line relationship between the voltage on T9 and torque on the motor WM. Potentiometer Rl3 is the one that bucks out magnetizing current and R-IZ changes the slope of the straight-line voltage-current relationship. This feature is claimed in my copending U. S. patent application Serial No. 655,699, filed March 20, 1946, for Control apparatus, said last-named application being also a division of said parent application Serial No. 534,111, mentioned above.

Commercial designations for the various tubes that are useful in the various locations are as follows:

Tubes 1 and 2 EL C6 J Tube 3 6N7 Values of other items in the circuit are designated on the drawings.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

Tube firing control apparatus for at least one gas-filled rectifier tube having an anode, a cathode and a grid, comprising an A. C.-potential circuit including a D. C. load and connected across said cathode and anode, the current of which circuit is rectified by said tube to feed said load, an adjustable D. C. network adapted to produce an adjustable D. C. potential component, a control tube having an anode non-inductively connected with the grid of said rectifier tube and having a grid connected to said adjustable D. C. network, an A. C. network having a potential in fixed out-of-phase relation to the A. C. potential impressed upon the anode of said rectifier tube, said A. C. network being also connected to said grid of the control tube, whereby the grid of the rectifier tube is supplied by the anode of the control tube with an adjustable firing voltage composed of an adjustable D. C. component and a fixed A. C. component undistorted between the said tubes.

ANTHONY WINTHER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,057,485 Haller Oct. 13, 1936 2,080,250 Bedford May 11, 1937 2,100,863 Lord Nov. 30, 1937 2,278,212 Meyer Mar. 31, 1942 

